The present invention regards a catheter device and method for the delivery of medication to a desired location within a patient""s body. More specifically, the present invention regards a device and method for reliable, simple and efficient delivery of a desired dose of medication to tissues within the body during minimally-invasive surgery procedures whereby a catheter handpiece is configured for deployment of a needle by the pressing of a single trigger and delivery of a desired dose of medication by pressing of another trigger.
The deployment in the body of medication and other substances, such as materials useful in tracking biological processes through non-invasive imaging techniques, is an often repeated and advantageous procedure performed during the practice of modern medicine. Such substances may be deployed in either case through non-invasive procedures such as endoscopy and through more invasive procedures that require larger incisions into the body of a patient. The non-invasive and less-invasive procedures are generally used when the target area is accessible through a lumen of the body, while the more invasive procedures may be employed when the target area is located deep within the body or otherwise not readily accessible through a lumen of the body.
Previously, injection of medication in minimally-invasive procedures required, among other complications, careful, time-consuming manual monitoring of the placement of the catheter tip within the body and the amount of medication or other substance being delivered during the injection procedure, potential exposure of the medication and other substances to the atmosphere during the handling of containers in preparation for dose injection, and, in the case of injection of multiple medications or other substances, time-consuming work to either remove and replace the catheter dose injection equipment or to prepare the equipment for re-use.
The present invention is directed to addressed the foregoing concerns with previous catheter injection systems. In one embodiment of the present invention, there is provided a drug delivery device for delivering a desired dose to an injection site within a patient""s body. The device includes a catheter handpiece, wherein the catheter handpiece has an outer handpiece body and an inner carriage assembly, and the inner carriage assembly can slide between a lumen end and an opposing actuator end of the handpiece body. The carriage assembly is biased toward the lumen end of the handpiece body by a spring. The handpiece body has an aperture through which a dose carpule is inserted to rest in the carriage assembly. An outer lumen is affixed to the lumen end of the handpiece body, and an inner lumen is affixed to the lumen end of the carriage assembly, such that when the carriage assembly slides toward the lumen end of the handpiece body, the inner lumen slides within the outer lumen a sufficient distance for the distal end of the inner lumen to extend beyond the distal end of the outer lumen, exposing an injection needle tip.
At the lumen end of the carriage assembly there is a dose carpule receiving flange. The proximal end of the inner lumen is affixed to the lumen end of the dose carpule receiving flange, which is configured to receive the dose carpule and guide the desired dose from the dose carpule into the inner lumen when a dose delivery actuator at the actuator end of the carriage assembly causes a dose delivery actuator to push on a piston within the dose carpule. Adjacent to the lumen end of the dose actuator is a dose carpule pressing block which presses the dose carpule toward the dose carpule receiving flange when an aperture door covering the handpiece body aperture is closed.
The catheter handpiece is prepared for use by actuation of an actuator cocking member located at the actuator end of the handpiece body. In this embodiment, the actuator cocking member is a knob which rotates about an axis parallel to the longitudinal axis of the carriage assembly. When the actuator cocking member is rotated by an operator, the carriage assembly is pulled toward the actuator end of the handpiece body until captured by the carriage release trigger, and a dose delivery actuator tube is rotated until captured by the dose release trigger. During the movement of the carriage assembly and the dose delivery actuator tube, the dose delivery actuator rod is prevented from being retracted by a ratchet mechanism. Once the catheter is located at the desired injection site within the patient""s body, the carriage release trigger may be actuated, whereupon the carriage assembly is released from its cocked position and slides toward the lumen end of the body, thereby extending the distal end of the inner lumen beyond the distal end of the outer lumen and causing the attached injection needle to penetrate the tissue at the desired injection site. Following deployment of the inner lumen, the dose release trigger may be actuated, whereupon the dose delivery actuator is released from its cocked position and a spring causes the dose actuator tube to rotate, which advances the actuator rod by means of a threaded dose delivery actuator nut through which the actuator rod passes toward the actuator end of the dose carpule. The actuator rod thus applies a force to the carpule piston to cause the desired dose to be delivered from the dose carpule through the dose carpule receiving flange and the inner lumen to the desired injection site. The amount of dose delivered is controlled by a dose metering member, which limits the motion of the dose delivery actuator tube, nut and rod, and thereby limits amount of medication discharged from the dose carpule. Following injection of the desired dose, the catheter handpiece may be cocked, withdrawing the inner lumen and injection needle back within the outer lumen. The catheter then may be repositioned to another desired injection location within the patient""s body for delivery of an additional dose from the installed dose carpule in the manner described above. The dose delivery process may be repeated until the desired number of doses have been delivered from the carpule, or the carpule is spent, whichever occurs first. When no further doses are to be delivered from the dose carpule, the catheter handpiece may be cocked to withdraw the inner lumen tip into the outer lumen prior to removal of the catheter from the patient""s body.
In a second embodiment of the present invention, the actuator is not powered by a spring, but instead the actuator rod moves toward the catheter end of the carriage assembly, thereby contacting and advancing the dose carpule piston, by manual turning of the actuator advancing knob at the actuator end of the handpiece body. Cocking of the needle release mechanism is accomplished by manual squeezing and pivoting of a cocking lever.
The present invention further includes a method for delivering the desired dose to a desired injection location. The method includes: (a) inserting a dose carpule through an aperture in the catheter handpiece affixed to the catheter into the carriage assembly and closing the aperture door in order to urge the dose carpule toward a receiving flange on the carriage assembly; (b) priming the inner lumen to remove air therein by setting a desired dose setting on a dose metering member in the handpiece body, rotating the actuator cocking knob on the end of the catheter handpiece opposite the catheter until the carriage assembly and the dose delivery actuator are in their respective cocked positions, depressing the carriage release trigger to cause the carriage assembly to slide toward the lumen end of the catheter handpiece, and depressing the dose release trigger to cause the dose actuator rod to apply a force to the dose carpule to cause the substance to be injected therein to pass from the dose carpule through the dose receiving flange and though the inner lumen and reach the end of the injection needle tip (this sequence is repeated until the medication reaches the injection needle tip); (c) rotating the actuator cocking knob on the end of the catheter handpiece opposite the catheter until the carriage assembly and the dose delivery actuator are in their respective cocked positions; (d) inserting the catheter including an outer lumen and an inner lumen into a patient""s body and maneuvering the catheter to a desired dose injection site; (e) depressing the carriage release trigger to cause the carriage assembly to slide toward the lumen end of the catheter handpiece and thereby cause the inner lumen affixed to the carriage assembly to extend beyond the distal end of the outer lumen into the desired injection site; and (f) depressing the dose release trigger to cause the dose actuator rod to apply a force to the dose carpule to cause the desired dose to pass from the dose carpule through the dose receiving flange, though the inner lumen and its injection needle tip and be deposited at the desired injection site. Alternatively, instead of depressing a dose release trigger, when using a non-spring powered embodiment of the present invention, the operator may advance the dose actuator rod toward the dose carpule by manually rotating the actuator advancing knob. Following dose delivery, the catheter handpiece may be cocked, withdrawing the inner lumen and injection needle back within the outer lumen. The catheter then may be repositioned to another desired injection location within the patient""s body for delivery of an additional dose by resetting the desired dose, depressing the needle release trigger, and depressing the dose release trigger or, in the second embodiment, turning the actuator advancing knob in the manner described above. The dose delivery process may be repeated until the desired number of doses have been delivered from the carpule or the carpule is spent, whichever occurs first, at which point the catheter handpiece may be cocked to withdraw the inner lumen tip into the outer lumen prior to removal of the catheter from the patient""s body.